For most people, buying a home is the biggest, most important investment of their lifetime. You want a home that functions well and is comfortable to live in. So it’s important to have a reliable, energy-efficient, money-saving central air conditioning system for you and your family.
During those long, hot summer days when the heat just won’t quit, it’s such a pleasure knowing you can retreat to a cool and pleasant home.
According to statistics, 64% of American homes use central air conditioning. And as summers get warmer, it’s likely that percentage will go up even higher.
If you are in the market to replace an outdated cooling system, it’s good to have a little knowledge up your sleeve. Any reputable dealer will appreciate the effort and will be able to answer your questions.
How to Choose
There are two major types of central air conditioners:
Split system: These have an outdoor cabinet which compresses and condenses the refrigerant, an indoor cabinet that houses the evaporator coil, and an air handler. The air handler is usually the part of the furnace that sends the cool air through the ductwork. For homes with furnaces, a split system could be the most economical to install.
Packaged system: In this system, all of the components are located in one cabinet; usually placed on a roof or on a slab next to the house’s foundation. Ducts go through the home’s exterior wall or roof to connect with the air conditioner outdoors.
Bigger isn’t always better. Way back in the 80s it wasn’t just big hair that was all the rage. Big air conditioning systems were the name of the game. That’s because electricity was cheap then (not like now!) and the technology only allowed for quick cooling. Today, energy efficiency is paramount. Today’s central air conditioners run in cycles, slowly but steadily lowering the temperature of your house instead of rapidly.
Too small? If your central air conditioner is too small for the square footage of your home, it will run constantly, costing you extra money and will have a very hard time keeping up on the hotter days.
Too Large? If the system is too large for the size of your home, it can hike up your energy bill. This is because it will cool your house too quickly, kicking off and on constantly. Too large a unit might not adequately reduce humidity.
Just Right! If you have a correctly sized unit, your central air conditioner will cool your home efficiently. It will go through a full cool cycle and then shut down for a while. This lowers your energy consumption and saves you money.
A central air conditioner’s size is measured in tons. The majority of central air conditioner manufacturer brands produce air conditioners in 1-5 tons, and going up incrementally by ½ ton measures.
A “ton” is a measure of an air conditioner’s ability to cool, not a measure of its weight. One ton is the ability of your air conditioner to cool 12,000 BTUs (British Thermal Unit) in an hour. What is a BTU? A BTU is the amount of energy required to heat or cool one pound of water by one degree Fahrenheit.
There are formulas to roughly calculate the correct size you need for the square footage of your house but these calculations also need to take into account the climate and region, how much insulation you have, the trees and shading around your house and even the height of your ceilings. It’s best to leave this to an expert.
Contractors who bid on your job should calculate required cooling capacity by using a recognized method such as one found in the ACCA’s Residential Load Calculation Manual, also called Manual J. An additional reference for assessing ductwork needs is Manual D. The calculations produce a detailed, room by room analysis of cooling needs.
Look for the Appropriate SEER Rating for Your Home
When buying an air conditioner, look for a model with a high efficiency rating. Central air conditioners are rated according to their seasonal energy efficiency ratio (SEER). SEER indicates the relative amount of energy needed to provide a specific cooling output. Many older systems have SEER ratings of 6 or less.
According to a U.S. Dept. of Energy bulletin, since 2015, SEER ratings of 14 are the minimum standard in Texas and other southern US states. And according to a more recent bulletin, 2023 requirements will be a bit higher, up to a SEER rating of 15 for the southern states. Some sources say that for best efficiency a higher rating of 18 or more is even better in a hot climate. The initial cost is higher but you will save in the long run.
A trusted contractor can help you choose the right size and SEER rating, so that your initial cost will save you money in the long run and be in line with your budget.
Single-Stage Compressors, Two-Stage Compressors, and Variable Speed Compressors
The main difference between these three types of central air conditioners is the type of compressor they use (the part of the AC that compresses the refrigerant).
A single-stage air conditioner’s compressor only works one level of operation— cooling your home at full blast.
A two-stage air conditioner’s compressor works at two levels of operations:
High for hot summer days (the equivalent of full blast for single-stage ACs) and low for milder days when you don’t need as much cooling.
A two-stage air conditioner will run on the lower setting until it gets too hot outside. Then it runs on the high setting to make sure you stay comfortable.
A variable-speed air conditioner’s compressor can run at different speeds depending on the cooling needs of your home. This makes variable-speed air conditioners much more energy efficient. It also keeps the indoor temperature more even, runs at a lower speed so it is quieter, and removes more humidity.
Of course, the variable speed air conditioner will save the most energy and money in the long run but is more expensive upfront.
Check with an expert to determine what is best for your needs.
Other Factors to Look For
Programmable thermostat. With a programmable thermostat, you can set your air conditioner and furnace to automatically run at previously selected energy saving temperatures when you’re away from home or in bed. You stand to save more energy because there’s no risk of forgetting to reset the thermostat.
A fan-only switch. This allows you to turn off the cooling but leave the fan running to circulate air for more natural, affordable cooling.
Energy Star rating. Earning the ENERGY STAR means the air conditioner meets strict energy efficiency guidelines set by the US Environmental Protection Agency. However, be aware that If you purchase a new energy-efficient air conditioner but connect it to an older furnace and blower motor, your system will not perform to its rated efficiency.
Warranty. Air conditioning warranties are important. Before purchasing a central air conditioning unit, ask for and read its warranty and be sure you understand the terms and restrictions.
If you’re in the market for a new central air conditioner, we can answer all your questions. Call Forney Air at (214) 924-9745 for a consultation with one of our experts.